Too much [potasium in blood test What can this cause or,what is the problem for the Heart

Dee Ann Lee,

Thanks for your question.

Elevated potassium levels can be caused by a few different situations.  The most common is a problem in the specimen of blood.  If the blood is allowed to sit too long before it is centrifuged into its components of plasma and blood cells (it's the plasma that is usually analyzed for the postassium), a process called hemolysis can occur.  This is a breakdown of the red blood cells and the release of the cellular content into the plasma, which raised the potassium level.  In most cases, the lab can indicate if the specimen was hemolyzed or not.  In this case, the blood test needs to be drawn again and processed quickly, and most patients values are normal.

Another common cause for high postassium is medication.  Some diuretics (dyazide, maxide) and high blood pressure medication (ace inhibitors)can cause elevations which is easily treated by switching to another medication if this is determined to be the cause.

Advanced kidney disease can cause high potassium levels and treatment for this can be complicated and beyond the scope of this forum.  This would be readily discovered on routine blood work.  In all likelihood, the patient would have several other symptoms of his kidney disorder and potassium levels would be monitored on a regular basis. 

Some complicated metabolic disorders can also cause high potassium levels, and patients would be quite ill long before their potassium would be affected.

Most labs have a range for "normal potassium" that spans from about 3.5 to 5.1.  Mildly elevated potassium poses no major problem to the heart.  When the level gets above 6.0, there is some concern for the development of abnormal heart rhythms.   

I hope this has been helpful.

Martin Cane, M.D.